The present invention relates to printing and displaying colors.
Typical printing and display devices can reproduce only a limited set of colors. The range of colors that can be faithfully reproduced by a particular display device or by a particular printing device on a particular printing medium is called a color gamut: the larger the gamut, the more colors can be reproduced. For example, glossy paper has a larger gamut than plain paper, because there are bright colors that can be printed on the glossy paper but not on the plain paper. Also, computer displays have typically larger color gamut than simple printers. To represent colors that are outside of the color gamut, a color device can use gamut mappings that map colors from outside to colors inside the gamut.
Designers use color charts to select colors for designing materials. Color charts can be device dependent or device independent. Device dependent charts present color samples that can be reproduced by a device on a medium. Examples of such color charts include Cyan-Magenta-Yellow-Black (“CMYK”) charts that are typically used in the printed press and include color samples with different percentages of Cyan, Magenta, Yellow, and Black inks. Alternatively, device dependent charts can use other color conventions, such as Red-Green-Blue (“RGB”) colors for designing material displayed on computer screens. A device dependent chart allows a designer to visually compare different colors as they will appear on the medium.
Device independent charts, for example, solid spot color charts, are typically used for cross-media publication, i.e., when a design is displayed or printed on multiple media or by different devices. Solid spot charts include a limited set of color samples mixed from high quality special inks of different colors to cover a large color gamut. For example, solid spot charts contain colors that cannot be printed with CMYK inks, so designers use cross reference charts to find the nearest CMYK color for each solid spot color.